I originally designed the HP-24 fuselage to be made of fiberglass, with a base layup of 5 plies of 7725, three at 0/90 and two +/-45. That was what George Applebay recommended. When we switched to carbon, I decided to simplify the layup at the expense of weight. Now we just use three plies of 11oz carbon, first and last at 0/90 and the middle one at +/-45. Plus reinforcements at the wing side of body and cockpit rail. The total thickness and fiber distribution is similar to what the Europeans are doing. After the shell cures, we add five or six ring stiffeners inside the aft fuselage, and the kit builder installs a bunch of bulkheads and longerons in the mid and forward fuselage areas. The only core foam is in the vertical fin; we put it down under the last 0/90 ply. The primary optimization here is getting a 22-foot long thing with 42 square feet of area laid up and bagged inside of two hours using relatively unskilled labor.As the thread is already called question for BoKu, I didn't want to open another another thread with the same name.
In the Raptor I got from the video that the fuselage is made from around 40oz or 1500g carbon with 1/2 inch core only in selected areas.
I seem to recall your HP-24 also has a fuselage without sandwich, so as also a lot of other gliders. I would like to know out of interest what thickness is generally used there?
From my smallest boat I know that there a sandwich of 2x6oz 2mm foam then 2x6oz again is substituted by 2x6oz, 3x12oz,2x6oz of glass for solid layups, doubling the weight in total.
Even kayaks only do this for white water, otherwise they switch to at least Soric if not Airex. So why in aerospace?
I don't understand. How does adding material save weight?... I was just wondering why not using Coremat (hand layup version of Soric), as this saves 40% of weight...
Just so, when it comes to panel stiffness against out-of-plane loads. And, of course, that panel stiffness helps resist crippling failures such as where the wall of a tube buckles when a bending moment is applied to it, so a sandwich tube might have more ultimate bending strength than a non-sandwich tube....Core thickness adds stiffness, the thicker the core the stiffer the end result of what ever your making...